<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">
    <title>Document</title>
  </head>
  <body>
    <script>
      var temp;
      var apple1 = '青苹果';
      var apple2 = '红苹果';
      temp = apple1;
      apple1 = apple2;
      apple2 = temp;
      console.log(apple1);		// 输出结果：红苹果
      console.log(apple2);		// 输出结果：青苹果
    </script>
  </body>
</html>